rtc-pl030.c

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/*
 *  linux/drivers/rtc/rtc-pl030.c
 *
 *  Copyright (C) 2000-2001 Deep Blue Solutions Ltd.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/module.h>
#include <linux/rtc.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/amba/bus.h>
#include <linux/io.h>
#include <linux/slab.h>

#define RTC_DR      (0)
#define RTC_MR      (4)
#define RTC_STAT    (8)
#define RTC_EOI     (8)
#define RTC_LR      (12)
#define RTC_CR      (16)
#define RTC_CR_MIE  (1 << 0)

struct pl030_rtc {
    struct rtc_device   *rtc;
    void __iomem        *base;
};

static irqreturn_t pl030_interrupt(int irq, void *dev_id)
{
    struct pl030_rtc *rtc = dev_id;
    writel(0, rtc->base + RTC_EOI);
    return IRQ_HANDLED;
}

static int pl030_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
    struct pl030_rtc *rtc = dev_get_drvdata(dev);

    rtc_time_to_tm(readl(rtc->base + RTC_MR), &alrm->time);
    return 0;
}

static int pl030_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
    struct pl030_rtc *rtc = dev_get_drvdata(dev);
    unsigned long time;
    int ret;

    /*
     * At the moment, we can only deal with non-wildcarded alarm times.
     */
    ret = rtc_valid_tm(&alrm->time);
    if (ret == 0)
        ret = rtc_tm_to_time(&alrm->time, &time);
    if (ret == 0)
        writel(time, rtc->base + RTC_MR);
    return ret;
}

static int pl030_read_time(struct device *dev, struct rtc_time *tm)
{
    struct pl030_rtc *rtc = dev_get_drvdata(dev);

    rtc_time_to_tm(readl(rtc->base + RTC_DR), tm);

    return 0;
}

/*
 * Set the RTC time.  Unfortunately, we can't accurately set
 * the point at which the counter updates.
 *
 * Also, since RTC_LR is transferred to RTC_CR on next rising
 * edge of the 1Hz clock, we must write the time one second
 * in advance.
 */
static int pl030_set_time(struct device *dev, struct rtc_time *tm)
{
    struct pl030_rtc *rtc = dev_get_drvdata(dev);
    unsigned long time;
    int ret;

    ret = rtc_tm_to_time(tm, &time);
    if (ret == 0)
        writel(time + 1, rtc->base + RTC_LR);

    return ret;
}

static const struct rtc_class_ops pl030_ops = {
    .read_time  = pl030_read_time,
    .set_time   = pl030_set_time,
    .read_alarm = pl030_read_alarm,
    .set_alarm  = pl030_set_alarm,
};

static int pl030_probe(struct amba_device *dev, const struct amba_id *id)
{
    struct pl030_rtc *rtc;
    int ret;

    ret = amba_request_regions(dev, NULL);
    if (ret)
        goto err_req;

    rtc = kmalloc(sizeof(*rtc), GFP_KERNEL);
    if (!rtc) {
        ret = -ENOMEM;
        goto err_rtc;
    }

    rtc->base = ioremap(dev->res.start, resource_size(&dev->res));
    if (!rtc->base) {
        ret = -ENOMEM;
        goto err_map;
    }

    __raw_writel(0, rtc->base + RTC_CR);
    __raw_writel(0, rtc->base + RTC_EOI);

    amba_set_drvdata(dev, rtc);

    ret = request_irq(dev->irq[0], pl030_interrupt, 0,
              "rtc-pl030", rtc);
    if (ret)
        goto err_irq;

    rtc->rtc = rtc_device_register("pl030", &dev->dev, &pl030_ops,
                       THIS_MODULE);
    if (IS_ERR(rtc->rtc)) {
        ret = PTR_ERR(rtc->rtc);
        goto err_reg;
    }

    return 0;

 err_reg:
    free_irq(dev->irq[0], rtc);
 err_irq:
    iounmap(rtc->base);
 err_map:
    kfree(rtc);
 err_rtc:
    amba_release_regions(dev);
 err_req:
    return ret;
}

static int pl030_remove(struct amba_device *dev)
{
    struct pl030_rtc *rtc = amba_get_drvdata(dev);

    amba_set_drvdata(dev, NULL);

    writel(0, rtc->base + RTC_CR);

    free_irq(dev->irq[0], rtc);
    rtc_device_unregister(rtc->rtc);
    iounmap(rtc->base);
    kfree(rtc);
    amba_release_regions(dev);

    return 0;
}

static struct amba_id pl030_ids[] = {
    {
        .id = 0x00041030,
        .mask   = 0x000fffff,
    },
    { 0, 0 },
};

MODULE_DEVICE_TABLE(amba, pl030_ids);

static struct amba_driver pl030_driver = {
    .drv        = {
        .name   = "rtc-pl030",
    },
    .probe      = pl030_probe,
    .remove     = pl030_remove,
    .id_table   = pl030_ids,
};

module_amba_driver(pl030_driver);

MODULE_AUTHOR("Russell King <[email protected]>");
MODULE_DESCRIPTION("ARM AMBA PL030 RTC Driver");
MODULE_LICENSE("GPL");